Population Structure & Change (SQA National 5 Geography): Revision Note

Specification checklist

This page covers what you need to know from the SQA National 5 geography specification to answer questions on:

• Factors affecting birth and death rates

Demographic transition model

• The demographic transition model (DTM) illustrates the five generalised stages that countries pass through as they develop

• It shows how the birth and death rates change and how this affects the overall population as the country develops

Stage 1

• The total population is low 

• High birth rates due to a lack of contraception/family planning 

• High death rates due to poor healthcare, poor diet and famine

• High infant mortality leads people to have more children, so that some children survive to adulthood

Stage 2

• The total population starts to rise rapidly

• Birth rates remain high as people continue to have large families

• Death rates decrease as a result of improved diets, better healthcare, lower infant mortality and increased access to clean water

Stage 3

• The total population continues to increase but the rate of growth slows down

• Birth rate starts to fall rapidly due to increased birth control, family planning, increased cost of raising children and low infant mortality rate 

• Death rate is still decreasing but at a slower rate, as improvements in medicine, hygiene, diet and water quality continue

Stage 4

• The total population is high and is slowly increasing

• The birth rate is low and fluctuating, as there is accessible birth control and more women are choosing to have fewer children and delay the age at which they start to have children

• The death rate is low and fluctuates 

Stage 5

• The total population starts to slowly decline as the death rate exceeds the birth rate 

• The birth rate is low and slowly decreasing

• The death rate is low and fluctuates

Population pyramids

• The characteristics of a population—the distribution of age, sex, ethnicity, religion, etc.—are known as the population structure

• The population structure is the result of changes in:

  • Birth rate

  • Death rate

  • Migration

• The two main components of age and sex can be shown on a population pyramid

• Population pyramids (also known as an age structure diagram) are a type of graph which can be used to illustrate the structure of a population

  • They illustrate the distribution of population across age groups and between males/females

• They enable governments nationally and regionally to assess the needs of the population for services such as healthcare and education

  • This means the governments can estimate and plan for spending

• As countries develop and pass through the stages of demographic transition, the shape of the population pyramid changes 

• The population pyramid can be used to identify the following groups:

  • Young dependents 

  • Old dependents 

  • Economically active (working population)

  • Dependency ratio 

• The least developed countries, like Niger, have a concave pyramid shape

• At the start of stage 2 of the demographic transition model

• This indicates:

  • High birth rate

  • Low life expectancy

  • High death rate but starting to decrease

  • High infant mortality rate

  • The young dependent population dominates

• Developing countries such as Nepal have a pyramid shape

• Stage 3 of the demographic transition model

• This indicates:

  • Decreasing birth rate 

  • Increasing life expectancy

  • Decreasing death rate

  • Decreasing infant mortality

  • Larger working-age population

• Developed countries such as the USA have a column-shaped

• Stage 4 of the demographic transition model

• This indicates:

  • Decreasing birth rate 

  • Increasing life expectancy

  • Decreasing death rate 

  • Low infant mortality

  • Larger working-age population

• Developed countries such as Japan have a pentagon shape with a narrowing bottom

• Stage 5 of the demographic transition model

• This indicates:

  • Decreasing birth rate 

  • Increasing life expectancy

  • The death rate is higher than the birth rate due to the ageing population

  • Low infant mortality

  • Ageing population

Issues caused by changing population structure

What is a dependent population?

• In all countries, there is a dependent population

  • These are people of non-working age

    • Youthful dependents 0-15 years

    • Ageing dependents over 65 years

• The dependent population relies on the economically active population 16-64 years old to support them

Demographic transition and dependent populations

• In stages 1 and 2 of the demographic transition model, the population is younger, with large numbers of dependent children

• In stages 3 and 4, the number of young people (under 15) starts to decrease

• In stages 4 and 5, the number of older people increases, creating a dependent ageing population

Developing countries and dependent populations

• High birth rates lead to high numbers of young (0-15 years) dependents in developing countries

• Although this leads to a large potential workforce in the future, there are disadvantages, including:

  • Poverty because parents are providing for large numbers of children

  • Unemployment occurs because there are more people than jobs available

  • Pressure on education and healthcare services

  • Pressure on housing leads to the building of informal settlements, which lack infrastructure and basic services (water and electricity)

  • Lack of formal employment leads to the growth of informal employment

  • Increased crime rates due to poverty and lack of employment

  • Overcrowding

Developed countries and dependent populations

• Low death rates and increased life expectancy mean that there are high numbers of elderly dependents in developed countries

• This can lead to:

  • Increased spending on healthcare because elderly people are more likely to need medical treatment

  • More public services, including hospitals and social services, are needed

  • Increased demand for care/retirement homes

  • Higher total cost of pensions leading to tax increases for the working population

  • Lower economically active population